Apparatus for selecting luminous points of an image for reproduction by television



June 10, 1930.

ETIENNE [KNOWN AS STEPHANE] JULIEN BRUN APPARATUS FOR SELECTING LUMINOUS POINTS OF AN IMAGE FOR REPRODUCTION BY TELEVISION Fil ed March 24, 1927 2 Sheets-Sheet l mun I a". g

INVENTOR.

June 10, 1930. 1,763,528

ETIENNE [KNOWN AS STEPHANE] JULIEN BRUN APPARATUS FOR SELECTING LUMINOUS POINTS OF AN IMAGE FOR REPRODUCTION BY TELEVISION Filed March 24. 1927 2 Sheets-Sheet 2 H L L r/vvE/v Tali if 747W v 714% Patented June 10, 1930 UNITED STATES PATENT OFFICE 4 ETIENNE (KNOWN AS STEPHANE) JULIEN BRUN, LYON, FRANCE APPARATUS FOR SELECTING LUMINOUS POINTS OF AN IMAGE FOE REPRODUCTION BY TELEVISION Application filed March 24, 1927, Serial No. 177,989, .and in France March 27, 1926.

The object of the present invention is to provide an apparatus for selecting the luminous points of an image and marking them in a much shorter time than that of )re vious devices and in great number so as to reproduce them at a distance in similar conditions.

The said apparatus essentially comprises two discs mounted on the same axis driven with a differential movement and formed with rectilinear slits which in one screen are arranged at an angle of substantially 45 to the radial slits in the other, in order to illuminate all the points of the image successively through the different intersections.

The invention also includes different dispositions whereby synchronism between the 7 selection and the reproduction of the images,

control, regulation and the transmission of colors, and vibratory movement suitable for transmission of electric Waves may be obtained.

In the annexed drawing, Fig. 1 is an ele- 2 vation of the apparatus facing the perforated discs;

Fig. 2 is a longitudinal section on the line A-A in Fig. 1.

Fig. 3 is a section on the line B-B in :0 Fig. 1. I

Fig. 4 is an' outside view of a detail of the synchronising mechanism; Fig. 5 is a front view of the current distributing plate;

Figs. 6, 7 and 8 represent the current regulator mechanism in elevation, profileand plan; and

Fig. 9 is a diagram of the different electric controls of the apparatus.

The apparatus comprlses two frames 1, which are connected by cross members fl and in which are mounted shafts 3, 4 and 5', driven at different speeds by toothed gears and pinions 9 and 10. On the shaft 4 is mounted one of the screens 6 while an external tube 7 concentrically arranged over shaft 4 carries another screen 8.

A small shaft 11 arranged at right angles to the above mentioned shafts, is driven by the shaft 5 through a worm 12.

The two discs .6 and 8 have on their peripheries, the one radiating slits and the other an equal number of slits, inclined at about 45 with respect thereto. The discs rotate at high speed with a predetermined difference, so that they are found periodically in the same respective position. The

period, in which all the luminous points are duce a vibratory current which, ampli ed,

will be transmitted by the transmitting station to the receiving station.

In order to permit the transmission of colors, the slits in one of the discs may have colored screens giving alternately the three complementary colors of the spectrum that is, red, yellow and blue screens so as to reproduce the same colors when receiving as when transmitting by means of a similar device. The duration of impression on the retina, colors, gives t e actual impression of the shades to be reproduced.

Television, which can be transmitted 10 wire or by electric Waves, is obtained wit two similar apparatus, one arranged for transmitting and the other for reception. The apparatus should turn exactly at the same speed.

In order to obtain synchronism, the appaermi ting the mixing of the ratus comprises a local horal control and The local horal control is provided by a clock 22, installed at each post with a second mechanism bea the-astronomical second and sending an e ectric signal at each second. On each a paratus counter mechanism also sends a signal to an electric minute mechanism provided with a second mechan- 28 arranged in proximity to the clock,- in order to facilitate comparison of the working of the clock and of the minute mechamsm,- which ought to be the same, each second comprising the number of images adopted.

The speed and periodic concordanpe regulator comprise an initial hand control through a starting rheostat. The electric current thus flows through a starting resistance of variable degree controllable at will. v

A centrifugal force regulator adjustable by hand, replaces the starting rheostat for the'motor when thedesired speed is attained.

The speed of the twoapparatus (transmitting and receivin being equal, it is possible for the periods constituting the image to overlap and the regularization i. e., the synchronism as distinct rom isochronism is completed by the mechanism to be hereinafter referred In operation the apparatus is driven by an electric motor M preferably of the umversal type, actuating the drivi through shafts 4 and? respectively, and are timed to drive the discs at a slight difference of speed with res t to each other permitting all the luminous lmage to properl pass throug the cooperating slits forme in discs 6 and 8.

By regulating the .relative speed of the discs it will be understood that the size of the slits will be vvaried whereby the best illumination and distinctiveness may be obtained.

Synchronism between the selection and the reproduction ofthe images is obtained by the two following successive regulations:

1.- The regulation of the s d of the motor as approximately as possi le by means of a hand controlled variable resistance 30, and such hand control can be replaced by automatic control during a long interval by means of a centrifugal force regulator 13 mounted on the regulating shaft 5, the regulator 13 having for its ob ect to fix the speed of the motor to one slightly higher than that required for synchromsm and,

2. The regulation of the speed determining perfect synchronism between two similar positions of the transmitti to and driven by the shaft 5. This disc 14 is" provided on its circumference with a tooth or projection 15 (Fig. 6) meeting a flexible shaft 3 onwhich is mounted the gears 9 an 10. These gears 9 and 10 rotate the discs 6 and 8' oints of anwas spring 16 so asto produce an ehicient light braki resistance of theapparatus at the desire point. The spring '1 produces only a momentary tor ue u on 14-and notacomlete arrest. T is exible spring 16 is ocked at its extremity in a movable mounting 17 arranged to damp the vibrations of the spring at the moment at which it leaves the cam 15,-allowing however the said spring to rise in the event of erroneous rotation in the o posite direction. The braking point may modified by an arrangement, to be hereafter referred to, turnable on the shaft 5 so as to harmonize the starting point of the formation of the image on the transmitting apparatus and the receiving'apparatus.

he cam is-retarded at every turn of the shaft 5 by the spring 16, except when the solenoid 21 comes into operation and'displaces it.

The flexible spring 16 can be moved from its normal position in order to escape the tooth 15, by means of the members 17, 18, 19 and 20 and an electro-magnet or solenoid 21' (Fig, ,7) receiving the electric si als from the local or regulating 0100 22 through the commutator 23.

The solenoid circuit is as follows 2 With reference to Fig. 9 it will be seen that the clock is connected to two terminals 22 and 22". Terminal 22 is connected to one terminel of the solenoid and 22 is con nected-to one'terminal of the commutator 23, the other terminal of the commutator 23 being connected to the other terminal of the solenoid 21. Expressed differently, solenoid 21, clock 22 and commutator 23, are arranged in series.

Support 18 is provided with an opening for passage of spindle 19. Spindle 19 can move horlzontally, in the sup ort 18 around screw 19" (upon operation 0 the lever 20), which screw holds a spring 19 bearing on a plate 19 which plate ,together with spring 16 is capable of upward movement in the event of erroneous rotation of 14 in an anti-clockwise direction.

' The solenoid 21, under the action of the electric current sent by the seconds-beatin regulating clock, after its passage throug the commutator 23 moves lever 20 and produces horizontal deviation of the mounting 17 and so brings about the escape of the flexible spring from the cam or tooth 15. Any suitable means may be employed for connecting lever 20 to s ring 16. This movement will take place w en the one of the two carbon brushes 24 which is placed furthest from and receiv- 23 ing apparatus, by means of a disc 14, keyed The commutator 23 comprises a disc of insulatin material mounted at the end of shaft 5 gsee Fig. 3) and making one turn per The shaft 5 which carries the Ill centrifugal force regulator as well as cam- 14 and the disc 23 takes its movement from the motor shaft 3 in the ratio 1 to 4. The gear ratios and motor speeds heretofore "given enable it to be established that shaft 5 makes 1 turn per image, since shaft 5 makes about 12 turns per second and discs 6 and 8 are arranged to make 12 turns per image by suitable gearing with the motor shaft.

On -the disc 23 (seeFig. 5) is placed a thin metal piece 23 of which the central part is in constant contact with one of the carbon brushes. of the commutator, whilst extension 23 gives contact with the other carbon brush. The said two brushes are contained in a block of insulating material and are pressed by two small spiral springs receiving current from two rings to which the electric current is brought by two leaf springs. This block is mounted on a shaft co-axlal with shaft 5 and to prevent it from being turned due to contact of the brushes with the commutator it is braked by means of two steel leaves between which, however, it may be turned by hand.

The speed of rotation of the discs being regulated elsewhere by the arrangements previously described, this block will have for its object to cause the apparatus to be braked each time the tooth 15 does not pass at the desired moment in front of the spring 16.

To establish the contact to operate the solenoid 21 and obtain a perfect synchronism the electrical clock 22 which beats seconds, sends at each second current from a battery 31 to the rotary switch or commutator 23 placed at the extremity of the shaft 5, lever 20 permitting solenoid 21 to bring the spring out of the path of the tooth 15 if the clock 22solenoid 21commutator 23 circuit is made at the required moment. The two carbon brushes 2 1 in contact with disc 23 make circuit for the current sent by the clock 22 when the two contacts fall on the metallic part. The current is, on the other hand, interrupted, when one of the brushes 24 is in contact with the insulating part.

To ensure regulation of the receiving apparatus in synchronism with the transmit ting apparatus, the commutator 23 (which is capable of varying the point where the signal should cease to act) is held so that the operator at the receiving station may rotate it by hand and so vary the point of braking until the image becomes correctly centered, the instants corresponding to the beginning of the period constituting the image, then being in harmony on the transmitting and receiving apparatus.

The transmitting post having similar apparatus to that at the receiving post each clock sends to the apparatus an electric signal at each second. The two apparatus being arranged to produce, say, twelve images per second the arrangement actuated by the electric signal from the clock will brake the movement so as to bring about harmony.

The operator at the transmitting post does not vary the moment of braking of the trans mitting apparatus this being done -only at the receiving station.

The displacement of the flexible spring 16 only takes place when the clock sign? corresponds to the position of the commutator. -The operator at the receiving station can thus, by feeling his way, find out the position of the commutator which is most favorable to the formation of a. distinct image on the receiving screen.

On the counting shaft 11 driven by the worm 12 at a speed of one revolution per second, is mounted a disc 25 graduated in fractions of seconds to allow the operator to appreciate differences of speed of the apparatus by checking with the local cloc which clock is regulated as exactly as possible on the astronomical second.

Shaft 11 rotates at one revolution per second in accordance with the aforesaid gear ratios of shafts 3 and 5 and with the motor speed adopted. A suggested range.

for motor speeds was given as 2500 to 3000 R. P. M.

Interaction of the cam 26 and lever 27 cause to be sent, at each turn of shaft 11, that is at each second (since shaft 11. rotates at 1 revolution per second) current from a battery 32 to a minute mechanism 28. With reference to Fig. 9 it will be seen that mechanism 28 having an hour-minutesecond dial similar to clock 22 and battery 32 are connected to the two terminals adjacent the terminals 22 and 22". The two former terminals are connected to the switch member 33 (see Fig. 4) contact between 3 1 and 35 effecting the sending of current through the mechanism 28, 34 and comeinto contact due to depression of the beak 36 caused by the said interaction of the cam 26 and the lever 27. nals are connected, the one, to 34 and, the other, to 35.

The minute mechanism 28 and the dial 25 (graduated in fractions of seconds) count the number of revolutions made by the shaft 11, shaft 11 rotating once per second. If shaft 11 does not, by error, rotate once per second this will be shown by comparison of the clock 22 with the mechanism 28 and dial 25.

Mechanism 28 being capable of adjustment with regard to the time of the clock or regulator 22, the difference of speed of the apparatus with that at which it must normally turn can be observed at each instant by comparison of the two dials. The

v dial of this minute mechanism (placed close to the clock and within reach of the op- The two said termic eckmg of the speed of the apparatus.

The minute mechanism 28 has for its object to check the synchronism of the ap paratus.

The re reduction of colors is obtained directly y using red, yellow and blue screens arranged on one of the discs ref erably on the face adjacent the remaining disc and covering the slits in the disc carrying said colored screens.

It is to be understood that the ap aratus shown and described is capable many modifications and those modifications that are within the scope of the claims, I consider within the spirit of the invention.

I claim: I

1. An apparatus of the character described comprising a driving shaft, gears carried by said shaft, a pair of discs each rotated in the same direction by the said gears and adapted to be driven at a different speed with respect to each other, one of said discs having radial slits and the others having slits formed at an angle substantially degrees with respect to the slits of the first mentioneddisc.

2. An apparatus of the character described comprising a pair of discs rotating concentrically in the same direction and with a differential movement, said discs having slits formed therein, the slits in one disc being formed at different an les to the slits in the remaining disc, and t e slits of both discs being arranged in rectilinear relation.

3. An apparatus of the character described comprising a pair of discs rotated concentrically in the same direction and with a differential movement, one of said discs having radial slits formed therein and the other having slits inclined at substantially 45 de rees with respect to the first mentioned s 'ts, said radial and inclined slits of the respective discs being arranged in rectilinear relation.

4. An apparatus of the character'described comprising a pair of discs rotated concentrically in the same direction and with differential movement, one of said discs having radial slits formed therein and the other having slits inclined at substantially 45 degrees with respect to the first mentioned shts and series of red, yellow and blue screens secured to one of said discs and covering the slits of the latter whereby to obtain a reproduction of colors. 5. An apparatus for selectin luminous points of an image for reproduction by television comprising a pair of discs rotated concentrically in the same direction and with a V difierential'movement, said discs ha slits formed therein the slits in one formed at a difi erent angle to the slits in mg the arranged 1n rectilinear relation, and an opaque screen in wbetween the image to be reprodu and the discs for the purpose'specified.

6. An apparatus for selecting luminous points of an image for reproduction by television, comprisi a pair of discs mounted to rotate concentrically in the same direction and with a differentlal movement one of said discs having radial slits formed therein and the other having slits inclined at substantially 45 degrees with respect to the first mentioned slits, said radial and inclined slits of the respective discs bein arranged in rectilinear relation, amotor or driving said discs, a double action centrifugal regulator controlling the speed of saidmotor, means for brakm the motor at a precise int, a clock re ated on the astronomical our for determining the movement of action of said motor braking means and adjustable means for varying the moment of action of said-braking means whereby to harmonize the starting point of the formation of the image on the transmitting and receiving apparatus.

7. An apparatus for selecting luminous points of an image for reproductionby television, comprising a pair of discs mounted to rotate concentrical y in the same direction and with a differential movement, one of said discs having radial slits formed therein and the other 'having slits inclined at substantially 45 degrees with respect to the first mentioned slits, said radial and in- 'clined slits of the respective discs being arranged in rectilinear relation, a motor for driving said discs, a double action centrifugal regulator controlling the speed of said motor, means for braking the motor at a precise point, a clock regu ated on the astronomical hour for determining the movement of action of said motor braking means and a dial indicator for the speed of the apparatus graduated in time unit and allowing of comparison with said clock.

8. An apparatus for selecting the luminous points of an image for reproduction by television comprising a motor for drivin said apparatus, a double action centrifugfi regulator controlling the speed of said motor, means for braki the motor at a precise point, a clock regfifited on the astronomical hour for determini the movement of action of said motor braki means, and adjustable means forvarying t e movement of action of said braking means whereby to harmonize the starting point of the formation of the image on the transmitting and receiving apparatus.

In witness whereof I have hereunto set my hand.

mama (it mill) JlIIJEN "III. 

